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Detecting BadBIOS, Evil Maids, Bootkits, and

Other Firmware Malware

SeaGL

October 6, 2017

Paul English, PreOS Security
Twitter: @penglish_preos
penglish@preossec.com

https://preossec.com/

personal blog of Lee Fisher (CTO):

https://firmwaresecurity.com/

Content licensed: CC by-SA4.0

http://creativecommons.Org/licenses/by-sa/4.0/

Agenda

Technology: some system/peripheral firmware.

Threats: types of and existing firmware-level
malware.

Tools: open source (and a few freeware) firmware
defect/security analysis tools.

Guidance: Introduce some basic advice for
protecting your firmware from attackers, mostly
based on NIST SP 800-147 lifecycle guidance.

About

Me:System Administrator since 1998, added “manager” more
recently. Former board member for the League of Professional
System Administrators (LOPSA), Board Member for Seattle
Privacy Coalition, organizer for Seattle Techno Activism 3 rd
Mondays

Employer: PreOS Security is a firmware security startup that
focuses on defensive tools for enterprises. I am co-founder and
CEO.

Presentation: discusses existing open source (and a few
freeware) firmware diagnostic/security tools, combined with some
existing NIST guidance. No new security exploits or
vulnerabilities or research.

Scope

Using ‘System Firmware’ aka ‘Platform Firmware’
(BIOS, UEFI, ACPI, etc.) definition of firmware, not
embedded OS firmware (eLinux, Windows loT,
Android, QNX, etc.).

Focusing on Intel x64 UEFI-based systems. Though
much applies to x86, AArch32, AArch64 UEFI
systems, and some BIOS systems.

Mostly focusing on UEFI-style systems, not coreboot
or U-Boot or other boot loader technologies.

Why are we talking about this?

Industry (standards bodies, governments):

- NIST SP 800-(147/147b/155/193) are guidance not policy, few follow it

- No mandatory policy explicitly requires addressing firmware security

Vendors (OEMs, ODMs):

- Most still shipping insecure systems

- None providing golden image hashes

- Insufficient changelog documentation

- Some never update firmware after initial release

Consumers (you):

- Most ignorant of the problem

- Not spending time to learn to solve problem

- Continuing to purchase insecure systems from vendors

NEXT MODULE

Tech

Threats

Tools

Guidance

Application

software

Operating system
software (and
IHV drivers)

Android

Linux

Windows

MacOSX

NanoBSD

Management
and SEE/TEE
firmware

SMM

Redfish

IPMI

L. J

r \

SMASH

It. JU

\ il

DASH

._j

r ”

Intel AMT

v_J

TrustZone

p 1

OP-TEE

L_J

fTPM

V_v

ARM-TF

( -"

System

firmware

Peripheral

firmware

coreboot

U-Boot

Hardware

CPU

GPU

TPM

Intel ME

BootGuard

AMD PSP

Rings of Protection

Early Intel processor security model (MS-DOS-era,
aka no security):

- Ring 3 (outermost): user mode, apps

- Rings 2-1: often not used.

- Ring 0 (innermost): kernel mode, drivers/OS kernel

Simplistic model, 3 (aka user space) and 0 (aka kernel
space), ignoring nuances of physical and virtual
firmware and silicon levels.

Invisible Things Lab (ITL) and others have proposed
adding new negative rings - below ring 0 - to clarify
this (next slide).

Negative (Subzero) Rings

Ring -1: VM, hypervisor/CPU (Intel VMX, AMD SVM)
Ring -2: Intel SMBIOS, SMM

Ring -3: Firmware (BIOS, UEFI, coreboot, U-Boot, ...)

Ring -4: hardware, silicon exploits

Firmware (-3) unites all of these rings: it is the gateway
to access SMM (-2) and HW (-4), and also works on
virtualized systems (-1), and can be accessed (and
controlled) by OSes/drivers (0) and apps (3).

We will be spending most of our time talking about ring
-3, focusing on UEFI-flavored firmware...

Intel Systems Mangement Mode

Systems Management Mode (SMM)

AKA “Ring -2”

Intel-based technology, mode of CPU other than
Real or Protect Mode, where attackers prefer to be
operating in. Basically, the first attempts of a
TEE/SEE for Intel x86 systems.

UEFI recently updated the Platform Initialization
(PI) spec, abstracts both Intel SMM and ARM
TrustZone as “MM”, Management Mode.

Image credit

Image from next slide comes from the Blackhat-
US-2017 presentation: "Firmware is the new
Black - Analyzing Past 3 years of BIOS/UEFI
Security Vulnerabilities", by Bruce Monroe &
Rodrigo Rubira Branco & Vincent Zimmer, Intel
Corp.

https://github.com/rrbranco/BlackHat2017/

Privilege

Modern x64 UEFI system arch

App

VM
App

BIOS & OS/VMM share access, but

t _ w

T t t w

1 l i

not trust

VMM / Hypervisor

UEFI + PI SMM

SMM / BIOS

\ 7 - 1

1 . i

Hypervisor can grant VM
direct hardware access

DMA

A specific Peripheral may have its own
processor, and its own firmware, which is
undetectable by host CPU/OS.

UEFI Services

UEFI Boot Services

- used by OS loader to transition from FW to OS
kernel (or boot manager, a pre-OS UEFI app)

- Only used during init, they're not available later.

UEFI RunTime Services

- Similar to BIOS interrupts like lOh (video) and 13h
(disk), UEFI has services that the OS uses.

- virtual memory, time, variables, console i/o, reset,
capsule, memory, event/timer, protocol, image

Image source: UEFI PI spec

Active Consoles

Input Console

Output Console

Standard Error Console

UEFI Boot Services Table

Task Priority Level Services
Memory Services
Event and Timer Services
Protocol Handler Services
Image Services
Driver Support Services

DXE Services Table

Global Coherency Domain Services
Dispatcher Services

Boot Services and Structures
Only available prior to OS runtime

UEFI

System

Table

UEFI Runtime Services Table

Variable Services
Real Time Clock Services
Reset Services
Status Code Services
Virtual Memory Services

Version Information
UEFI Specification Version
Firmware Vendor
Firmware Revision

System Configuration Table

DXE Services Table

HOB List

ACPI Table

SMBIOS Table

SAL System Table

Runtime Services and Structures
Available before and during OS runtime

Secure Boot

Secure Boot is an optional build-time feature of
UEFI 2.x using multiple sets of keys to try and
secure the firmware from malware.

UEFI Variables Secure Boot Databases:

- Platform Key (PK)

- Key Exchange Key Database (KEK)

- Secure Boot Signature Database (db)

- Secure Boot Blacklist Signature Database (dbx)

- Secure Boot Timestamp Signature Database (dbt)

- Secure Boot Authorized Recovery Signature
Database (dbr)

More secure boot flavors

Besides default (insecure) boot modes of past,
more secure boot modes are being used, to help
detect attacks:

- UEFI Secure Boot

- TCG Measured Boot (uses TPM)

- Trusted Boot (uses Intel TXT)

Related technologies:

- coreboot Verified Boot (Android, ChromeOS)

- U-Boot Verified Boot

Image credit

https://github.com/rrbranco/BlackHat2017/

Intel/UEFI boot sequence

CPU/SOC

(Intel)

Start Block
PEI

BIOS

DXE/UEFI

OS Loader/Kernel

(OSV)

Measure

(OEM)

Intel® Boot
Guard

Measure

(OEM)

Executable

Measure

Enforces

Executable

Enforces

Policy

Intel® Device Protection
Technology with Boot Guard

http://www.intel.com/content/dam/www/public/us/en/docu

ments/product-briefs/4th-een-core-familv-mobile-brief.pdf

OEM PI
Verification
Using PI Signed
Firmware Volumes

Vol 3, section 3.2.1.1
of PI 1.3 Specification

OEM UEFI 2.7
Secure Boot

Chapter 27.2 of
The UEFI 2.4
Specification

ACPI

Advanced Configuration and Power Interface

Successor to ISAPnP, APM and MP.

ACPI used by both BIOS and UEFI. Initially only
on Intel, now also on ARM systems.

Dozens of ACPI ‘tables’ are defined.

ACPI has an AML (ACPI Machine Language) and
bytecode which the firmware and OS has to run.

The UEFI Forum owns the ACPI specifications.

Image source: ACPI spec

I - ACPI Spec Covers this area
I - OS specific technology, not part of ACPI

- Hardware/Platform specific technology, not part of ACPI

PCIe

PCIe is one of the main peripheral busses these days.

In addition to main system firmware ROM, each PCIe
device on the system can have option/expansion ROMs
on their flash, often BIOS-based code as well as UEFI-
based drivers, that enhances the platform firmware to
support the PCIe device.

NVMe and Thunderbolt are PCIe-based.

See CHIPSEC_util’s PCI command

Recent Apple Mac EFI firmware has new boot key to press
to disable loading of PCIe device option ROMs.

Other: USB, Hard disks, Monitors?

“BadUSB”

https://github.com/brandonlw/Psychson

Hard disks (and SSDs): on-board controller.
Sprites: http://spritesmods.com/?art=hddhack

Monitors! - MonitorDarkly

https://github.com/redballoonshenanigans/monitor

darkly

NEXT MODULE

Tech

Threats

Tools

Guidance

Why Threaten Firmware?

Stealth

- As current tools & practices do not address firmware,
compromises can remain undetected

Persistence

- Even if detected, issues can be more difficult to fix at the
firmware level. Nobody wants to throw away hardware.

Full Access

- “Ring 0” or even “Negative Ring” access operate below
most protection. Some protection relies on firmware
features!

Evil Maid attack

The “Evil Maid” attack is perhaps the best-known firmware
attack.

Results from physical access to hardware, game over.

Evil Maids attack unattended systems, like the laptop left
at a hotel while out at dinner, handed to TSA, insecure
server room,...

Attacks vary, from plugging in rogue
PCIe/USB/Thunderbolt peripheral, attaching SPI/JTAG
device, to complex de-chipping.

Never leave unsecure computers unattended.

Supply Chain Verification

New hardware is bad enough

- Vendors do not provide golden image hashes for verification

- Most vendors do not provide sufficient documentation for firmware
features, or for updates, to distinguish changes in ROM that are vendor
updates -vs- attacker malware.

- Shipped hardware may be be intercepted by government agencies, or
criminals in shipping companies; interdictions of shipped hardware,
infected with malware.

Grey market hardware is much worse

- Basically the same problem as interdictions. Do you know how to
factory-reset the firmware of all the used hardware you’ve acquired?

Industry has no mechanism to verify silicon for threats.

Physical and network security

Data centers and 'server rooms' should have good physical security.

Desktops left at work are often accessible by evil maids in night shift
cleaning staff.

Mobile devices have roaming network security issues.

Mobile devices left in hotels subject to evil maid attacks.

New airline travel (“Travel 2.0”) restrictions enables evil maid attack
for phones/laptops/etc of more and more travelers.

Firmware management OOB network management must be
isolated, encrypted, and authenticated (Intel AMT, Redfish, IPMI,
iLO, ...). Previously Ethernet-centric, now WiFi-based OOB
solutions make this even harder to isolate.

Firmware Updates and OS attacks

With UEFI, firmware updates are more standardized than
with BIOS, and are now more easily called by user-mode
applications. Recent OS platform integration has firmware
updates included in OS updates (eg: Windows Update).

If vendor has not locked down their firmware update
mechanism to signed code and signed payloads, attacker
can pivot off an OS root/admin exploit to embed bootkit into
firmware.

There are lots of OS/app-level security tools and rules out
today: do any watch for (and selectively disallow) firmware-
updates?

Existing UEFI malware

The CHIPSEC project maintains a blacklist for UEFI
malware, currently has 3 entries:

- Hacking Team’s Vector-EDK

- @cr4sh’s ThinkPwn

- CIA Mac EFI malware

A few security researchers have some POCs on Github.
Old leaked goverment malware:

- NSA(BIOS, not UEFI): DeityBounce, BananaBallot, JetPlow

- CIA (Mac EFI): DarkMatter, DerStark, QuarkMatter, ...

UEFI Secure Boot keys

UEFI uses PKI for Secure Boot and code
signing. UEFI does not have CRL/OSCP for
checking for bad keys.

The UEFI Forum maintains a list of bad keys
used by UEFI Secure Boot. There are a few
dozen entries in current DBX.

Does your vendor provide tools to update the
DBX? :-)

Hardware attacks

Hardware attacks:

- USB, Hak5 USB Rubber Ducky, etc.

- PCIe, PCILeech-based, DMA/other attacks by
‘rogue hardware’ (inexpensive COTS dev board)

- Thunderbolt

- Rowhammer, memory attacks

Open Source == shared
vulnerabilites

OEM vendors share a common core UEFI
codebase (tianocore.org).

Next slide, image source:

https://twitter.com/XenoKovah/status/62348324489

0189824

“Dear firmware makers: ALL UEFI-RELATED
FIRMWARE LOOKS THE SAME TO ATTACKERS!
YOUR SECURITY THROUGH OBSCURITY IS
GONE!”

Image source:

https://twitter.com/XenoKovah/status/623483244890189824

Firtlonniw Jt

sub_7S€2i62
iub_79C2l6S

7 SrtHcm

T sub 7*2171

jne»o<245
;&& n a x

MacBookAir4,l

ASUS BT1AH (from our CanSecWest 2015 talk)

loc 79F2BA72:

now

rex, [r 1 S« 0 fl 0 h|

call

CoreRestorelpI

now

rex, (ris«ermt)

call

CoreFreePool

now

cs:q»ord /9I31SDS, r12

now

Wx, rib

call

sub 79E28F12

test

rsi, rsi

short loc_79F 2B6B9

uiia-3

test

rdi, rdi

short loc_79E2BAB9

now

rib, (r15«(W0h)

now

[rdi], rib

now

rib, [r1S*Q88h]

now

[rsi], rib

jnp

short loc 79E2B6D0

i -

loc_7»E2B6B9:

«ou rex, [r1S«0B8ti]

call CoreFreePool

wou _ qiioi d ptr [r1S» IKIBh |,

±jL

loc_79E2B6D6:
now rib, (r15« UflHh J
test

rlli, rib
short loc 79E2B6E3

idle Down

100.00% 21S.1648) (116.170) 0000X67* 0000000079I2B675: Cor«SurtlB43«*lS9

Disk: 1SSB

=—a

/ mb.iaooooxo
7 •ub.iaoooojoc

/ aub_1600003S8
r Pub_i600004l4

r *wb_i800004lC
T iub_ 160000428
7* «ub_140000460
7* Pub_16000049C

A 160000V90

7* «ub.160000620
7" sub _ 160000704

7 *cb_ 1600007S8

r Pub. 1600007E8
7 Pub.180000640
7 sub_10OOOO6A0

f Pub _ 16000086 8
7 Pub. 160000900
7 sub_16000092C
^pub 100000X40

Une SS3 of 1209
Graph ©v □ (9

loc 18081FBO7: ; supposed to be lnaQe->fpl

now rex, (rbxM OADE0 IMAGE PR IUATE.0010 . Ipl |

call CoreRestif’elpl

now rex, ( rbx«LOftDEO_IMftCE_PRIUftTE_DftfA . JunpContext ) ; supposed to

call CoreFreePool

now rex, r12 ; r12 - HandleOatabaseKey

piow cs:nCurrent!naqe, r13
call CoreConnectHandlesByKey

test rsi, rsi ; rsi - ExitData

jz_short loc 1BBB1EC1E ; supposed to be lpiaqe->lxitData

u- -

test rdi, rdi ; rdl - ExltOataSlze

jz _ short loc_180P1EC1E ; supposed to be lnage->ExltData

osed to be Inaqe->ExitDataSize
osed to be Inaqe->ExitOata

status - Inaqe >Status

±jL

1oc_ 18001EC1E: ; supposed to be

now rex, (rbx*0C0h]

CoreFreePool

qword ptr (rbx»0C8h], 8 ; suppose

call

and

▼ f

; Status - Inaqe->Status

1 88 Oh]
loonoooooanati

XU: 1 <U« Down

|l8081ECbF

> p

1100.00% <634.1707) (2.107) 0001KBOC D00000016001EBDE Cor*St*rtIaa«*-»13X
Disk: 1SSB

Firmware Bug Classes

• 1) Inconsistent power-transition checks

• 2) Race Condition

• 3) Trusting input

• 4) Measurement failures

• 5) Platform capability not properly configured

• 6) Security of meaningful assets exposed to untrusted entities

• 7) Hardware Misbehavior

• Classes defined in the Blackhat-US-2017 presentation: "Firmware is the new
Black - Analyzing Past 3 years of BIOS/UEFI Security Vulnerabilities", by
Bruce Monroe & Rodrigo Rubira Branco & Vincent Zimmer, Intel Corp.
https://github.com/rrbranco/BlackHat2017/

NEXT MODULE

• Threats

• Tech

•Tools

Guidance

Tool Scope

These tools, as with presentation scope, are mostly
focusing on UEFI and ACPI.

Tools not covered: Intel ME, Intel AMT, IPMI, Redfish
USB, microcode, etc. Tool coverage for these varies!

Two kinds of tool usages for firmware:

- Live: testing against a live running system

- Offline: testing a rom.bin or other file (NVRAM UEFI
variables, ACPI tables, etc.), earlier generated by live
tools.

Core Live Tools by OS

Linux: CHIPSEC, acpidump, FWTS, FlashROM, Google

Pawn, ls(hw,pci,usb), ...

macOS: CHIPSEC, acpidump, Apple eficheck[l],

DarwinDumper (FlashROM), ...

Windows: CHIPSEC, acpidump, WinFlashROM,
RWEverything[l], ...

UEFI Shell: CHIPSEC, acpidump (2), multiple shell commands
RU.efi[l], many built-in shell commands,...

FreeBSD: FlashROM, acpidump

[1] closed-source freeware, other tools are open source.

Core Offline Tools

CHIPSEC

ACPICA (ACPI trade group) tools (acpidump
etc.)

FWTS

UEFI Firmware Parser

UEFITool

UEFIDump

CHIPSEC

https://github.com/chipsec/chipsec

The McAfee (formerly Intel) CHIPSEC Project is a framework for analyzing the
security of Intel x86 and x64 systems including hardware, system firmware
(BIOS/UEFI), and platform components.

CHIPSEC does both online analysis of live systems - bare metal and multiple
virtualized targets - as well as offline analysis of system images. It includes a
security test harness with multiple security modules. It can be run on Windows,
Linux, Mac OS X and UEFI shell.

CHIPSECjmain is a set of security tests, roughly one module per public
vulnerability. CHIPSEC_util is a collection of tools - including fuzzers - to explore a
system, eg. to dump rom.bin via SPI. Main and Util share a common “HAL” driver, a
native OS kernel driver, for accessing various low level interfaces, and forensic
capabilities. The Python-based tool also includes a library that other tools can use.

Attendees: grab a CHIPSEC quick reference sheet before you leave!

ACPIdump

https://www.acpica.org/source

The ACPI Component Architecture (ACPICA) project provides
an operating system (OS)-independent reference
implementation of ACPI. The complexity of the ACPI
specification leads to a lengthy and difficult implementation in
operating system software. The primary purpose of ACPICA is
to simplify ACPI implementations for OSVs by providing major
portions of an ACPI implementation in OS-independent ACPI
modules that can be integrated into any OS.

ACPICA includes a handful of ACPI tools, ACPIDump, ACPI
Extract, etc.

FWTS (Firmware Test Suite)

https://wiki.ubuntu.com/FirmwareTestSuite/Reference

Firmware Test Suite (FWTS) comprises of over fifty tests that
are designed to exercise and test different aspects of a
machine's firmware.The tools read UEFI, BIOS, ACPI, IPMI
and other platform firmware. FWTS was created by Canonical
to help test systems, and works on Ubuntu, and other Linux
systems but not BSD or Windows. FWTS has a Linux kernel
driver to test UEFI Runtime Services. FWTS has both a
command line and a CURSES Ul.

FWTS also has a liveboot Linux distribution called FWTS-live
which can be used to run the tests, using the CURSES Ul.

FlashROM

https://www.flashrom.org/Flashrom

https://github.com/pinczakko/winflashrom

flashrom is an open source utility for identifying, reading,
writing, verifying and erasing flash chips. It is designed
to flash BIOS/EFI/coreboot/firmware/optionROM images
on mainboards, network/graphics/storage controller
cards, and various other programmer devices. It
supports parallel, LPC, FWH and SPI flash interfaces
and various chip packages. It works on most Unix-like
systems, and there is a Windows port.

Apple eficheck

https://apple.com/

Recent versions of Apple macOS High Sierra
have a new utility called ‘eficheck’. It can dump
your system rom into a file (eg, a rom.bin) as well
as perform some security analysis, including
performing weekly scans of the rom.

If there’s a problem with firmware, eficheck can
opt-into uploading the image to apple.com for
them to analyze.

UEFITool (and UEFIDump)

https://github.com/LongSoft/UEFITool

UEFITool is a powerful cross-platform C++/Qt program for parsing,
extracting and modifying UEFI firmware images. It supports parsing of
full BIOS images starting with the flash descriptor or any binary files
containing UEFI volumes.

UEFITool is a Qt GUI tool, but the project also includes a few Qt-free C+
+ command line tools, UEFIDump, UEFlExtract, and UEFIPatch. The
main parsing engine and most of the command line tools are not Qt-
dependent. (UEFITools' 'UEFIDump' is like a non-GUI version of
UEFITool, and is different from FWTS's 'uefidump'.)

For an example of using UEFITool, look at Intel Security's Advanced
Threat Research team's blog post with analysis of the Hacking Team's
UEFI malware, they use CHIPSEC and UEFITool to analyze it.

UEFI Firmware Parser

https://github.com/theopolis/uefi-firmware-parser

UEFI Firmware Parser is a Python module and set of scripts
for parsing, extracting, and recreating UEFI firmware volumes.

This includes parsing modules for BIOS, OptionROM, Intel ME
and other formats too. It supports: UEFI Firmware Volumes,
Capsules, FileSystems, Files, Sections parsing, Intel PCH
Flash Descriptors, Intel ME modules parsing (ME, TXE, etc),
Dell PFS (HDR) updates parsing, Tiano/EFI, and native LZMA
(7z) [decompression, Complete UEFI Firmware volume object
hierarchy display, Firmware descriptor [regeneration using the
parsed input volumes, and Firmware File Section injection.

DarwinDumper

https://bitbucket.org/blackosx/darwindumper

DarwinDumper is collection of open source tools to dump Apple
Mac OS X system information to aid troubleshooting. It dumps
ACPI tables, DMI, EFI memory, EFI variables, SMC keys, system
BIOS, etc. It has a privacy mode which omits some serial
numbers and machine-unique data from the resulting report.

Tools include: bdmesg, cmosDumperForOsx, dmidecode,
dumpACPI, edid-decode, fdisk440, FirmwareMemoryMap,
flashrom, getcodecid, genconfig, getdump, gfxutil, iasl, ioregwv,
Izma, nvram, oclinfo, Ispci, RadeonDump, radeon_bios_decode,
smbios-reader, SMC util, VoodooHDA.kext, x86info.

EFIgy

https://efigy.io/

Duo Security just released EFIgy yesterday!

EFIgy checks the EFI firmware of Apple Mac
systems.

UEFI Shell-based tools

The UEFI Shell has nearly a hundred commands, many powerful

diagnostics for low-level firmware/hardware information. No other OS

in your way, either.

- Fairly easy to build a USB thumb drive to boot a system into the UEFI Shell,
instead of it’s default OS.

Sample of some of built-in commands:

- Bcfg, Dblk, Devices, DevTree, DH, Disconnect, DMem, DmpStore, DP,
Drivers, DrvCfg, DrvDiag, EfiCompress, EfiDecompress, GetMTC, IfConfig,
Load, LoadPCIROM, Map, MemMap, MM, Openlnfo, Parse, PCI, Reconnect,
Reset, SMBIOSView, ..

Samples of some external third-party commands:

- CPython 2.7x, CHIPSEC, acpidump, FPMurphy’s UEFI Utilities, UefiTooIPkg,
Vim, Intel EFI Disk Utilities, ...

Read and Write Everything

http://rweverything.com/

RW, aka RWEverything (Read and Write Everything) is a GUI
Windows-based firmware utility that enables access to almost all
the computer hardware, including PCI (PCI Express), PCI
Index/Data, Memory, Memory Index/Data, I/O Space, I/O
Index/Data, Super I/O, Clock Generator, DIMM SPD, SMBus
Device, CPU MSR Registers, ATA/ATAPI Identify Data, Disk Read
Write, ACPI Tables Dump (include AML decode), Embedded
Controller, USB Information, SMBIOS Structures, PCI Option
ROMs, MP Configuration Table, E820, EDID and Remote Access.

It ships with Win32 or Win64 binaries, and is freeware, not open
source.

Read Universal utility

http://ruexe.blogspot.tw/

The Read Universal utility is a multi-function tool
for BIOS debugging. It includes tools that
provides direct access to almost all resources
like memory, IO space, PCI, SMBIOS data, UEFI
variables and so on.

The tool is freeware - not open source - and is
written by a UEFI Engineer at AMI. It ships as
ru.exe and ru.efi binaries.

Linux UEFI Validation (LUV)

https://01.org/linux-uefi-validation

Aka: LUV, LUVos, luvOS, LUV-live, ‘the LUV shack’.

LUV is a UEFI test-centric Linux distribution from Intel that helps test UEFI
implementation issues for Linux. It bundles multiple external tests (FWTS,
CHIPSEC, BITS, etc.), runs them all in batch-mode, saves results for later
review. LUV is based on Yocto Linux, and works on Intel x86 and x64 systems.

LUV provides integrated testing, such as the interaction between the
bootloader, Linux kernel and firmware, that require cooperation across multiple
runtime phases. Enables LUV to test UEFI capsule updates work correctly
across a reboot.

LUV-live is a LUV-based liveboot distribution. It boots via a thumb
drive or via PXE, and runs in batch mode and gathers up test results.

Linux UEFI Validation (LUV)

https://01.org/linux-uefi-validation

Aka: LUV, LUVos, luvOS, LUV-live, ‘the LUV shack’.

LUV-live is a LUV-based liveboot distribution. It boots via a thumb
drive or via PXE, and runs in batch mode and gathers up test results.

Vendor-Specific Tools

Many OEMs/IBVs add diagnostic tools.

- OEMs provides tools for business-class systems, and rely on IBV
for tools for ODM-based consumer-class systems.

Examples:

- Multiple (HP, Dell, Cisco, etc.) have UEFI diagnostic tools on their
boot menus.

- Microsoft’s Surface has optional enterprise-only firmware, with
security features unavailable in consumer firmware.

- Lenovo’s TPM reset CD and UEFI diagnostic CD.

- Apple Store’s Geniuses have access to a tool that can reset your
firmware password.

PreOS vaporware announcement

PreOS Security is creating a new open source firmware tool
for SysAdmins, SRE, DFIR, Blue Teams, and advanced users.

It gathers data about firmware (UEFI, ACPI etc.) via invoking
multiple firmware tools, starting with CHIPSEC and FWTS,
more tools planned.

It targets Linux on Intel x64 UEFI systems. More arch/OS
targets planned, x86, AArch64, Windows, macOS, more Linux
distros.

For announcement of availability, firmware security tips, sign
up at:

https://preossec.com/newsletter

NEXT MODULE

Threats

Tech

Tools

Guidance

Next few slides have some advice taken from existing
sources

1) CHIPSEC team interviewed for an article in
DarkReading.com, with 5 basic tips for firmware
security.

2) NIST has 3 documents with ‘secure BIOS’ advice, for
enterprises, including a secure BIOS platform lifecycle.

I’ve added some of the existing tool suggestions for the
various phases of the NIST secure BIOS platform
lifecycle. Don’t blame NIST for those suggestions!:-)

DarkReading’s 5 tips

Credit to:

http://www.darkreading.com/iot/5-tips-for-prote

cting-firmware-from-attacks/d/d-id/1325604

1) Know that the threat is real.

2) Practice security basics: Least privilege,
Physical access controls, Disable unnecessary
services, firewalls, Antivirus, Incident Response
plans and drills, etc.

Dark Reading (cont’d)

3) Benchmark for vulnerabilities: write protection
secure boot, blacklist, cert revocation

4) Make a firmware golden image, check
periodically, particularly after an incident

1) Also do this for test results (eg: CHIPSEC for UEFI)

2) When tests are updated, re-run

5) Think broadly about firmware: presence in
many aspects of a system, many types of
hardware, automated vs. manual updates.

NIST secure BIOS guidance

2011: SP 800-147: BIOS Protection Guidelines

- Protects systems from unauthorized BIOS modification by defining a secure,
non-bypassable authenticated update mechanism.

2011: SP 800-155: BIOS Integrity Measurement Guidelines (Draft)

- Outlines a framework for a secure BIOS integrity measurement and reporting
chain for client systems, to detect unauthorized modification of System BIOS and
configuration using secure measurement and reporting mechanisms.

2014: SP 800-147B: BIOS Protection Guidelines for Servers

- Extends SP800-147 system model, from simple PC to more sophisticated
servers with BMC and OOB update mechanisms.

2017: SP 800-193: Platform Firmware Resiliency Guidelines (Draft)

- Provides technical guidelines and recommendations supporting resiliency of
platform firmware and data against potentially destructive attacks.

NIST SP 800-147 Platform Lifecycle

• Guidance is both for device vendors, as well as
enterprise sysadmins - but YOU are the (only) sysadmin
for your own personal system(s) usually.

• 5 States of firmware lifecycle, covering acquisition to
disposition:

- Provisioning

- Platform Deployment

- Operations and Maintenance

- Recovery

- Disposition

Pre-Provisioning: Before Purchase

Vendor research

- RFP, request CHIPSEC logs

- Don’t buy the system if it fails CHIPSEC’s security tests

- Goal is to avoid purchasing insecure systems.

Set company purchase policy about what HW/FW features must
be in new models.

- Require new systems to have features listed in NIST
147/155/etc to provide firmware security

- Eg, All new Intel UEFI systems must pass all current relevant
CHIPSEC security tests.

- Eg, UEFI instead of BIOS, must have TPM v2, etc.

Provisioning: Pre/+Deployment

Test CHIPSEC, confirm logs did pass, if not return the system!

Follow your policy:

- Using/disabling silicon security tech (VT, TPM, TXT, TZ, TEE, Intel-ME, ...)

- Using/disabling ports/hardware (WiFi, USB, Thunderbolt, BT, Ethernet, ...)

- Smartcard authentication for boot/network access Secure/Trusted/Measured/Verified Boot

- Clarify system boot order

- WakeOn<N> features

- No unencrypted storage (Self-Encrypting Drives, SEDs, NVMe + TPM)

- Firmware/BIOS password

- Selecting UEFI over CSM/LegacyBoot

- Limit ‘pre-OS’ software installed (UEFI drivers, services, apps, UEFI shell scripts)

- Check ESP, look for startup.nsh (unlike autoexec.bat, there can be N of these, in any directory, if in UEFI
Shell's %PATH%)

- Look for *.efi, look on OEM/IHV flash for OpROMs and UEFI drivers

- Control/disable net access (IPMI, PXE, HTTP Boot, SMASH and DASH, Redfish, ...)

Enable Secure Boot!

- Enable signed code: All vendor & 3 rd party code should be signed!

- Some sites may wish to use their own keys, instead of default UEFI CA

- Ensure DBX file is up to date

Maintain “golden” image for each platform, all firmwares and state

- Compare golden images, ACPI tables, UEFI variables, compare image with vendor-supplied image or hash, save archive

- Create and maintain configuration baseline

- Maintain a copy of the RTU, if applicable

- Register endpoint identity and BIOS integrity information in system inventory

Operations: Maintenance &

Monitoring

Update! OS standardized and NIST SP 800-147 authenticated if possible eg:

- Windows via Windows Update (from Win 7 onward)

- Linux via fwupd

- Mac via App Store updates

- Vendor specific (eg: Eve’s USB ethernet adapter firmware update v.0.4 -
v0.5)

Measurelafter firmware updates - dump images, ACPI tables, UEFI variables.

Periodic/Regular firmware scans: (eg: re-run CHIPSEC, dump ACPI tables,
UEFI vars)

- After updates

- When new tests are available

Network - isolate, authenticate, encrypt and monitor all firmware network traffic

- UEFI HTTP[S] Boot, IPsec, iSCSI, PXE, AMT, DASH, SMASH, IPMI, iLO,
etc.

Recovery

After a security incident...or suspected incident including BUT NOT
LIMITED TO:

- Loss of physical control of machine

- Known Evil Maid Attack

- OS level compromise

Take full validation steps:

- regenerate image

- rerun tests

- compare image, ACPI tables, UEFI variables & test results with originals,
looking for signs of infection. eg,SPI protections were enabled, now
disabled

- Use forensic tools eg: chipsec_util.py to parse SPI image

Disposition

• Reset BIOS/UEFI configuration to defaults

• Remove passwords and organization-specific cryptographic keys

• Remove organization-specific customizations

• Reset any TPM secrets

• Sanitize media

• UEFI has user data, User ID and Smartcard drivers, for PXE remote boot and
IPsec use (CHAP auth used somewhere).

• Be clear on what user credentials are stored in your firmware, before you recycle
it!

• Ask your vendor how to purge Pll from their firmware product, for safe disposition.

- Eg, Lenovo has a CD that resets the TPM data.

Summary

Understand the firmware security problem, start
with NIST SP 800-147’s lifecycle.

Learn to use the tools to help you protect your
firmware, start with CHIPSEC.

PreOS Security has an upcoming ebook that
covers this topic.

PreOS Security has an upcoming firmware test
tool to help you diagnose your firmware.

Credits

Thanks to my business partner & CTO of
PreOS Security, Lee Fisher for developing this
talk.

Thanks to many people on the firmware-
security list on Twitter, the edk2-devel mailing
list, from the CHIPSEC and FWTS projects for
answering questions. Thanks to many other
security researchers for their tools and firmware
research.

Questions?

Comments?

Thanks for attending!

Free e-book, quarterly newsletter, software announcements:

https://preossec.com/newsletter

Paul English
penglish@preossec.com

@penglish_preos

https://preossec.com

https://firmwaresecurity.com (personal blog of Lee Fisher, CTO of
PreOS Security)

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